VOC-Less Electrostatic Fluid Dispensing Apparatus

ABSTRACT

Systems and methods for rapidly atomizing and dispensing electrostatically atomized insecticides and similar low electrical conductivity active materials without the use of VOCs. The active materials are dispensed via insertion of a disposable cartridge in a dispensing apparatus. The dispensing apparatus is hand actuated and the exhausted cartridge is minimized to the size of a wad of chewing gum and it is doubly sealed to prevent any residual active material from leaking into the environment. Spray flow and configuration may be user selectable.

BACKGROUND OF THE INVENTION

Embodiments of the present invention generally relate to systems andmethods for dispensing electrostatically atomized active materialswithout the use of volatile organic compounds (“VOCs”). Morespecifically, embodiments of the present invention generally relate tosystems and methods for rapidly atomizing and dispersing insecticidesand similar low electrical conductivity fluids without the use ofpropellants and other additives.

The aerosol can dispenser is a staple of modern society. Produced by thebillions, the modern aerosol can is capable of dispensing, on demand,high flow-rate (gram/sec), finely aerosolized doses of a wide array ofproducts. Despite its continued refinement and utility, the aerosol candispenser is a fundamentally inefficient and polluting means for spraygeneration and transfer of active material to a target.

By way of example, a popular, archetypical insecticidal aerosol can hasa net weight of about 370 grams (13 ounces) of which the activeingredients (Pyrethrins) and “related” materials (including “petroleumdistillate”) account for less than 2% of the total weight ofingredients. The remaining “inert” material, some 98.087%, is requiredfor the aerosolization process. To atomize and disperse less than eightgrams of active material requires in excess of 360 grams ofenvironmentally detrimental propellant/diluent plus a costly pressurevessel and atomizing nozzle.

The aerosol can dispenser is simply a hydraulic or gas assisted nozzle.Operational pressure (of about 5 bar), consisting of hydraulic pressure,propellant vapor, or a combination of the two, mechanically andaerodynamically converts bulk fluid into a directed droplet plume. Witha broad droplet size distribution characterized by a significantpopulation of small (<10 micron) droplets, these readily stagnatedaerosols also present a respirable health hazard. This highlyinefficient atomization and dispersal process is effective, but it is soat a cost. The environmental impact of the propellants dumped into theatmosphere, discarded pressure vessels, and the inhalation healthhazards of repeated exposure to the spray are costs that have yet to beto be fully addressed.

Well-proven direct charge injection electrostatic atomizer technologyprovides high instantaneous flow rates of the small volumes of activeingredients required for all applications of interest. Charged spraydroplets so produced are self-dispersive, preferentially enveloping andwrapping around the target. Transfer of fluid to the target isinherently more effective than is possible using conventional aerosoldispensers. Of equal importance, the charged spray cannot form arespirable cloud. Having droplet size distributions three or more timesnarrower than non-charged sprays, small (<10 microns) and large (≧100microns) droplets are absent. All droplets are charged, attracted to thetarget, and cannot be inhaled.

Most importantly, modest feed pressures (less than one bar) available byhand pumping are sufficient to generate self-dispersive small dropletplumes. This capability permits the elimination of VOCs such aspropellants and diluents as well as the high-pressure containerpreviously required for atomization/dispersion. However, currentmanifestations of direct charge injection electrostatic atomizers arebulky and costly.

What is needed is an alternative aerosolization and/or dispensingapparatus that eliminates the propellants and/or diluents inherent inaerosol can operation. It is an object of this invention to provide adisposable, hand-held, low-pressure electrostatic atomizer capable ofproviding the same level of low-cost, operator-friendly convenience ofan aerosol can without detrimental impact on the environment or userhealth and in which only “active”, undiluted ingredients are sprayed.

BRIEF SUMMARY OF THE INVENTION

Disclosed is a portable apparatus for electrostatically dispensing fluidincluding: an activating mechanism; a high voltage generator to providea high voltage; a power source to supply power to said high voltagegenerator; a disposable cartridge; a pressurizing mechanism connected tosaid activating mechanism to be driven thereby, said pressurizingmechanism located adjacent said disposable cartridge and incommunication with a second end of said disposable cartridge fordeforming and pressurizing said disposable cartridge; a housing, saidhousing substantially enclosing at least a portion of said activatingmechanism, said high voltage generator, said power source, and saidpressurizing mechanism, said housing including a first cartridgereceptacle for detachably receiving said disposable cartridge; and aspray charge dissipation mechanism.

The disposable cartridge includes: a reservoir containing said fluid; afluid output channel extending from said reservoir through an exteriorwall of a first end of said disposable cartridge; and a movable orificestructure located adjacent and external to said exterior wall of saidfirst end of said disposable cartridge, said movable orifice structureincluding at least one exit aperture, a conductor, and an insulator,said at least one exit aperture passing through said conductor, saidconductor electrically grounded when said disposable cartridge islocated in said dispensing position, said insulator positioned to coveran external end of said fluid output channel and said emitter electrodewhen said movable orifice structure is located in a non-dispensingposition thereby isolating said emitter electrode and said fluid from anenvironment external to said disposable cartridge, said movable orificestructure connected to said activating mechanism to be positionedthereby relative to said channel when said disposable cartridge islocated in said dispensing position; an emitter electrode including anemitter electrode tip and an emitter electrode contact, said emitterelectrode contact located exterior to said disposable cartridge and saidemitter electrode tip located internal to said disposable cartridge,said emitter electrode contact electrically connected to said highvoltage generator for electrostatically charging said fluid when saiddisposable cartridge is in a dispensing position, said emitter electrodetip positioned to substantially axially align with one of said at leastone exit apertures when said movable orifice structure is in saiddispensing position; and an emitter electrode channel extending fromsaid emitter electrode tip to said fluid output channel, said emitterelectrode channel axially aligned with said emitter electrode tip.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings embodiments,which are presently preferred. It should be understood, however, thatthe invention is not limited to the precise arrangements andinstrumentalities shown. In the drawings:

FIG. 1 is a schematic view of an apparatus for electrostaticallydispensing fluid in accordance with one embodiment of the presentinvention;

FIG. 2 is an exemplary electrical circuit diagram of the apparatus ofFIG. 1 in accordance with one embodiment of the present invention;

FIG. 3 is an angled cross-sectional view of a disposable cartridgehaving a linear orifice structure;

FIG. 4A is an exploded view of the linear orifice structure of thedisposable cartridge depicted in FIGS. 1-3;

FIG. 4B is an assembled interior view of the linear orifice structure ofthe disposable cartridge depicted in FIGS. 1-4A;

FIG. 4C is an assembled exterior view of the linear orifice structure ofthe disposable cartridge depicted in FIGS. 1-4B;

FIG. 5 is an angled cross-sectional view of a disposable cartridge of anapparatus for electrostatically dispensing fluid having a rotary orificestructure in accordance with an alternate embodiment of the presentinvention;

FIG. 6A is an exploded view of the rotary orifice structure of thedisposable cartridge depicted in FIG. 5;

FIG. 6B is an assembled interior view of the rotary orifice structure ofthe disposable cartridge depicted in FIG. 5;

FIG. 6C is an assembled exterior view of the rotary orifice structure ofthe disposable cartridge depicted in FIG. 5;

FIG. 7A is a cutaway interior view of an encased rotary orificestructure for use with the apparatus depicted in FIGS. 1-3; and

FIG. 7B is a cutaway exterior view of the encased rotary orificestructure of FIG. 7A.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology may be used in the following description forconvenience only and is not limiting. The words “lower” and “upper” and“top” and “bottom” designate directions in the drawings to whichreference is made. The terminology includes the words above specificallymentioned, derivatives thereof and words of similar import.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methods,constructs and materials are now described. All publications mentionedherein are incorporated herein by reference in their entirety. Wherethere are discrepancies in terms and definitions used in references thatare incorporated by reference, the terms used in this application shallhave the definitions given herein.

The objects of the present invention can be achieved by anelectrostatic, self-contained fluid dispensing device which can behand-held and hand operated and includes a disposable fluid cartridge.In addition to containing the spray fluid, each cartridge has an orificestructure and an integral direct charge injection emitter electrode tofacilitate electrostatic atomization. This inexpensive atomizer iscapable of providing a convenient, high, instantaneous flow-rate andcontrolled-dosage spray profile equivalent to that provided by anaerosol can.

The exhausted disposable plastic cartridges can reduce the eco-footprintto that of a wad of chewing gum. Residual active material is trapped inthe exhausted cartridge, is doubly sealed against leakage, and isenvironmentally benign. The dispensing device includes a housing whichencloses a power source for the electrostatic atomizer and an activatingmechanism for producing pressure for the fluid cartridge and for movingan orifice structure. The housing includes a receptacle for acceptingand removably holding the fluid cartridge. When placed into thereceptacle, the fluid cartridge makes electrical connection with thepower supply and mechanical connection with the activating mechanism.

The activating mechanism is at least partially situated within thehousing to provide a sufficient amount of pressure within the fluidcartridge and adequate movement of the orifice structure when apredetermined amount of pressure and motion is applied thereto viaactivation of the mechanism by an operator. The mechanism is activatedby the operator squeezing a handle or other mechanical lever. Thereplaceable cartridge is sized to provide single or multiple dosages ofconcentrated active ingredients, preferably about 10 mL to about 60 mL.

Hand-activation of the device simultaneously activates an atomizer andapplies pressure to the fluid within the fluid cartridge sufficient topropel the fluid out of the fluid cartridge. Activation of the atomizerincludes moving an orifice structure having exit apertures such that atleast one of the exit apertures aligns with a fluid output channel andan emitter electrode tip, thereby allowing the fluid to beelectrostatically charged inside the fluid output channel to allow foratomization and dispersion of the fluid after it exits the device.

Linear Orifice Structure

Referring first to FIG. 1, depicted is a schematic view of a dispensingapparatus 100 for electrostatically dispensing fluid. Dispensingapparatus 100 includes, inter alia, housing 102, pressurizing mechanism104 (shown in a fully extended position), disposable cartridge 106,cartridge receptacle 116, disposable cartridge emitter electrode contact108, power supply 110, spray charge dissipation mechanism 112, andactuator cavities 114.

The ergonomic housing 102 is configured to be hand-held and to providesufficient space for all components used in the apparatus. Suchcomponents include, but are not limited to, for example, cartridgereceptacle 116 for receiving and removably holding cartridge 106, powersupply 110, electrical circuitry 202 (FIG. 2), pressurizing mechanism104, spray charge dissipation mechanism 112, and activating mechanism(not shown) the latter of which includes, inter alia, pressurizingmechanism 104 and lever 226 (FIG. 2). The approximate size of housing102 and its component is indicated by the 10 mm scale depicted in FIG.1.

Cartridge receptacle 116 preferably comprises a securing mechanism forremovably securing cartridge 106 within cartridge receptacle 116.Examples of suitable securing mechanisms include, but are not limitedto, friction fittings, pins, screws, spring-loaded pins, spring loadedlatch(es), and the like. The securing mechanism can be manually orautomatically engaged when cartridge 106 is fully placed withincartridge receptacle 116.

In one preferred embodiment, cartridge 106 is held securely withincartridge receptacle 116 via engagement of one or more lockingreceptacles 230 with corresponding spring-loaded, semi-spherical pinsmounted to, or passing through, a wall of cartridge receptacle 116. Uponinsertion of cartridge 106 into cartridge receptacle 116, eachspring-loaded pin is sufficiently depressed into the wall of cartridgereceptacle 116 to allow cartridge 106 to pass into cartridge receptacle116. Full insertion of cartridge 106 into the proper position withincartridge receptacle 116 causes alignment of the spring-loaded,semi-spherical pins with their corresponding locking receptacles 230,thereby allowing the spring-loaded pins to release into lockingreceptacles 230 and thereby locking cartridge 106 into cartridgereceptacle 116. Such locking prevents or minimizes movement of cartridge106 within cartridge receptacle 116 particularly during pressurizationof cartridge 106 and/or activation of lever 226. As cartridge 106 isfully exhausted, pressurizing mechanism 104 travels further intocartridge receptacle 116 and causes one or more disengagement extensions234 to exert pressure on the spring-loaded, semi-spherical pins causingthem to depress and disengage from locking receptacles 230. This allowsthe operator to easily remove cartridge 106 from cartridge receptacle116 when cartridge 106 is exhausted.

In the embodiment of the present invention depicted in FIGS. 1-4C,electrical circuitry 202 includes voltage converter 204 for providingsufficient high voltage to power emitter electrode 318 as well ascomparator circuitry 206, the latter of which provides the operator withindication of one or more operational statuses of the apparatus. DC-DCvoltage converter 204 converts the voltage from power supply 110 to avoltage sufficient to power the electrostatic atomizer, preferablywithin the range of −5 kV to −10 kV or −500 V to −15 kV with outputcurrents within the range of −1 μA to −10 μA or −1 μA to −100 μA.

In one embodiment of the present invention, the output of the DC-DCvoltage converter 204 includes short protection to avoid damage todispensing apparatus 100 in the event that one or more of exit apertures212 become clogged, or otherwise inoperable, or an electrical short iscaused due to the presence of foreign matter in the inter-electrode(emitter-orifice) region. That is, DC-DC voltage converter 204 cantolerate continuous shorting of its output without damage. The outputvoltage ripple of DC-DC voltage converter 204 is preferably less than3%, but generally can be 10%, or larger, due the accommodating design ofdispensing apparatus 100. Dispensing devices such as dispensing devices100, which are not subject to breakdown and spray disruption fromvoltage excursions and/or variations, are inherently insensitive topower supply variations caused by voltage ripple at the levels notedabove.

The design of DC-DC voltage converter 204 of dispensing device 100 isoptimized to achieve low cost production having a preferred cost of lessthan $10 per unit. More expensive converters may be substituted withoutdeparting from the scope of the present invention, for example, asdictated by market requirements. Preferably, DC-DC voltage converter 204has a total volume of less than 20 mL, however, larger volume converterand converter designs may be easily accommodated within housing 102 ofthe dispensing apparatus 100. In one embodiment, DC-DC voltage converter204 circuitry is separated between two or more interconnected modules topermit them to be distributed within the confines of housing 102 ofdispensing apparatus 100 while providing the same functionality as asingle circuit board DC-DC voltage converter.

Power supplies 110 may include, but are not limited to, for example:disposable batteries including, without limitation, one or more AAbatteries and one or more 9 volt transistor batteries; replaceable orrechargeable batteries; fuel cells; solar power; alternators; andmechanically actuated generators including, without limitation, piezo-or tribo-electric generators actuated by lever 226. In one embodiment,power supply 110 includes three (3) AA batteries, which is electricallyconnected to electrical circuitry 202 as depicted in FIG. 2 and willprovide the requisite fixed output voltage of DC-DC voltage converter204 as the power supply 110 voltage varies with use from approximately4.8 V to approximately 3.6 V.

Comparator circuitry 206 accepts current from orifice structure 208,lever 226 (which is a conductive operating lever in the depictedembodiment), and spray charge dissipation mechanism 112. Spraydissipation may include, but is not limited to, for example, a staticwick or drag-line which acts to dissipate spray charge build-up to theambient atmosphere. In one embodiment, spray charge dissipationmechanism 112 is commercially available static wick material built intohousing 102 which facilitates a convenience of use similar to that of anaerosol can.

In an alternate embodiment of the present invention, spray chargedissipation mechanism 112 is one or more brush strips including, withoutlimitation, Ultra Stat® Static Elimination Brushes as manufactured byUltrafab, Inc. This dissipation mechanism is capable of dissipating theapproximately one μA spray current generated by dispensing device 100,which is important for achieving continuous spray operation. In oneembodiment, the length of the linear brush strips is less than 20 cm,and the length of the bristles thereof is approximately 6 mm long. Thissize allows the brush strips to be easily integrated into dispensingdevice 100.

In yet another alternate embodiment, spray charge dissipation mechanism112 is an anti-static paint such as that manufactured by AntiStaticIndustries. In one such embodiment, an approximately 3 cm by 4 cm swatchof anti-static paint is applied to the base of housing 102 of dispensingdevice 100. However, alternate spray charge dissipation mechanisms maybe substituted for any of those discussed above including, withoutlimitation, thoriated, lanthanated, or cesiated tungsten wires,reconstructed oxide-metal composites, and 325 by 325 0.0014″ diameterstainless steel wire mesh.

Based on the relative levels of these three currents, comparatorcircuitry 206 actuates appropriate indicators 210 to indicate status tothe operator including, but not limited to, for example: apparatus 100is in stand-by mode; apparatus 100 is operating properly; cartridge 106is empty; and/or one of exit apertures 212 is clogged and a new exitaperture 212, if applicable, must be moved into place. Indicators 210include, but are not limited to, for example, lights, buzzers,vibrators, and other visual, mechanical, and/or audible alarms.

More specifically, in the absence of current flow to spray chargedissipation mechanism 112, structure orifice 208, and/or lever 226,comparator circuitry 206 indicates that apparatus is in stand-by mode(or its non-dispensing position). Once apparatus 100 begins sprayingfluid 310, current flow to spray charge dissipation mechanism 112,structure orifice 208, and/or lever 226 begins. Upon sensing same,comparator circuitry 206 indicates to the operator via an indicator 210that apparatus 100 is operating properly. In addition, when cartridgedepleted switch 220 is actuated by indicator extension 218, the changein position of switch 220 indicates to comparator circuitry 206 thatpressurizing mechanism 104 is fully extended and replacement ofcartridge 106 is required. Lever action, in the absence of both currentto spray charge dissipation mechanism 112 and a signal from switch 220that cartridge 106 is depleted, indicates that orifice structure 208 isclogged, defective, and in need of substitution or replacement.

As best seen in FIGS. 1 and 3, pressurizing mechanism 104 providessufficient pressure to fluid reservoir 302 to eject fluid 310 throughfluid output channel 314, past emitter electrode tip 320, and out ofcartridge 106 through exit aperture 212. In a preferred embodiment,pressurizing mechanism 104 is a piston and a mechanism for moving thepiston, such mechanism coupled to lever 226 and actuated by an operatorof apparatus 100.

Fluid 310 is contained within fluid reservoir 302 of cartridge 106 byorifice structure 208 which acts to seal fluid output channel 314 whenit is located in a non-dispensing position. Fluid 310 may be anynon-conductive fluid including, but not limited to, for example,insecticides, lubricating oils (e.g., WD-40), cooking oils (e.g.,Canola, Soy, Olive, and Corn oils), fragrances, pharmaceuticals,grooming products, coatings, and the like.

Pressurizing mechanism 104 is located internal to housing 102, and itengages cartridge 106 after insertion thereof into cartridge receptacle116. Pressurizing mechanism 104 moves longitudinally within cartridge106, thereby applying pressure to fluid reservoir 302 as pressurizingmechanism 104 moves into cartridge 106.

In a preferred embodiment, pressurizing mechanism 104 includes indicatorextension 218 external to cartridge 106, which moves along withpressurizing mechanism 104 and which engages cartridge depleted switch220 when fluid 310 is fully expended from fluid reservoir 302 andpressurizing mechanism 104 has moved to the end of its range of motion.The change of position of cartridge depleted switch 220 due toactivation of same by indicator extension 218 causes comparatorcircuitry 206 to indicate a cartridge empty alarm to the operator via,for example, an indicator 210, thereby notifying the operator that thecartridge is in need or removal or replacement.

Pressurizing mechanism 104 also includes one or more disengagementextensions 234, which, at the end of its range of motion, disengages oneor more cartridge securing mechanisms to unlock cartridge 106 fromcartridge receptacle 116. Disengagement extensions 234 also disengageorifice structure 208 from the activating mechanism, thereby allowing anoperator to remove cartridge 106 from cartridge receptacle 116 andhousing 102.

Housing 102 includes an activating mechanism for activating one or moremechanisms within apparatus 100 including, but not limited to, orificestructure 208 and pressurizing mechanism 104, ultimately resulting inthe initiation of one or more atomized sprays. Such an activationmechanism could include one or more solenoids and switches, mechanicallinkages and gears, any combination thereof, or the like.

When cartridge 106 is fully secured and seated in cartridge receptacle116, it causes a number of things to occur, including, but not limitedto: 1) cartridge 106 is secured to housing 102 by one or more securingmechanisms; 2) mechanical and electrical connections are establishedbetween the activating mechanism and the moveable orifice structure 208;and 3) emitter electrode contact 108 physically contacts voltageconverter contact 228 thereby causing voltage converter 204 to supplypower to emitter electrode 318 for energization of the latter.

Requiring the secure seating of cartridge 106 in cartridge receptacle116 prior to energization of voltage converter 204 assures absoluteisolation of the operator from the internal high voltage source providedby voltage converter 204 to converter contact 228 since orificestructure 208 is located in the non-dispensing position prior toinsertion of cartridge 106 into housing 102. That is, as discussed ingreater detail herein, in the non-dispensing position, insulator 402 oforifice structure 208 covers emitter electrode 318 and fluid outputpassage 314 thereby isolating the environment external to apparatus 100from fluid or current flow.

In one preferred embodiment, cartridge 106 includes a pin 224 having anupper pin section 224 a and a lower pin section 224 b. Insertion ofcartridge 106 fully into cartridge receptacle 116 causes lower pinsection 224 b to actuate a water-proofed cartridge insertion statusswitch 222 mounted on pressurizing mechanism 104, thereby establishingan electrical connection between power supply 110 and electricalcircuitry 202. This electrical connection energizes voltage converter204 and comparator circuitry 206. Comparator circuitry 206 grounds theorifice structure and indicates various operational statuses including,but not limited to, the status of the insertion of cartridge 106.

In addition to establishing an electrical connection, the engagement oflower pin section 224 b with the water-proofed cartridge insertionstatus switch 222 mounted on pressurizing mechanism 104 ensures theazimuthal positioning of cartridge 106. Such positioning is important toensure that emitter electrode contact 108 makes contact (and anelectrical connection) with the recessed converter conductor 228.

The mechanical connection of orifice structure 208 to the activatingmechanism occurs via engagement of notches 418 with indexing structuresof the activating mechanism as discussed in greater detail below withregards to FIGS. 3 and 4A-4C.

Turning now to FIG. 3, depicted is an angled, cross-sectional view ofdisposable cartridge 106 having a linear orifice structure 208.Disposable cartridge 106 includes a substantially cylindrical reservoir302, the topmost end of which includes dispensing apparatus 304.Dispensing apparatus 304 includes head 306, emitter electrode 318, fluidchannel 314, locking receptacle 230, and orifice structure 208.

In one embodiment of the present invention, cartridge 106 ismanufactured of a thin walled, flexible, electrically insulatingmaterial including, but not limited to, for example, polyethylene,polypropylene, or other flexible polymers having good to excellentelectrical and mechanical properties. The use of such material allowsthe bottommost portion of the walls of cartridge 106 to fold into itselfdue to the force exerted by pressurizing mechanism 104 as it progressesupward and into cartridge 106. This force decreases the size ofreservoir 302, thereby applying pressure to fluid 310. This is best seenin FIG. 3 in which cartridge 106 is shown in a partially exhaustedcondition, pressurizing mechanism 104 having folded the rearward casingof cartridge 106 inward.

In a preferred embodiment, the shape of pressurizing mechanism 104closely conforms to that of cartridge 106 to allow pressurizingmechanism 104 to fold the cartridge in a manner that minimizes theamount of fluid 310 trapped between the interior folded surfaces ofcartridge 106. This feature minimizes the waste and environmental impactassociated with the discarded cartridge 106. Alternate embodiments maybe substituted including, but not limited to, for example, cartridgeshaving accordion pleating.

Cartridge 106 includes a pin 224 having an upper pin section 224 a and alower pin section 224 b. Upper pin section 224 a is substantiallycylindrical and fits tightly into fluid output channel 314 whencartridge 106 is fully exhausted. When cartridge 106 is completelyexhausted, the walls of cartridge 106 are collapsed upon and pressedagainst reservoir upper interior wall 328, thereby sealing any fluidtrapped within the interior folded walls, creases, or crevasses ofdepleted cartridge 106 from leakage to the environment. In thisposition, upper pin section 224 a is forced into fluid output channel314, precisely mating therewith and thereby facilitating the spraying ofany residual fluid 310 from cartridge 106. That is, when cartridge 106is in an almost completely exhausted state, upper pin section 224 islocated internal to fluid output channel 314 and any fluid remaining inpin cavity 326 is electrostatically atomized by emitter electrode 318,thereby forcing the atomized fluid 310 out of cartridge 106 through thecorresponding exit aperture 212.

Once cartridge 106 is completely exhausted and pressure is released fromlever 226, orifice structure 208 returns to its non-dispensing state,thereby causing any minimal residual fluid trapped within the interiorfolded walls, creases, or crevasses of depleted cartridge 106 to beredundantly sealed within the depleted cartridge 106 (and from leakageto the environment) via the contact between the uppermost end of upperpin section 224 a and fluid output channel 314 with interior face 330 oforifice structure 208. This sealing occurs prior to the removal of thedepleted cartridge 106.

The topmost portion of reservoir 302 is bounded by head 306. Face 312 ofhead 306 is substantially planar and is located at an angle ofapproximately thirty (30) degrees relative to the axis of substantiallycylindrical reservoir 302. Substantially cylindrical fluid outputchannel 314 passes from reservoir 302 through head 306 in alignment withone or more exit apertures of orifice structure 208 when such structureis located in a dispensing position.

Emitter electrode 318 includes emitter electrode contact 108 and emitterelectrode tip 320. Emitter electrode contact 108 is embedded in thesubstantially cylindrical outwardly facing wall 322 of disposablecartridge 106. Emitter electrode tip 320 is positioned toward fluidoutput channel 314. The position of emitter electrode tip 320 relativeto the exit aperture 212 aligned with fluid output channel 314 is thatwhich best achieves the desired operating voltage for emitter electrode318. Typical distances between emitter electrode tip 320 and exitaperture 212 vary from a minimum of approximately one half of the radiusof exit aperture 212 to a maximum of two to four times the length of theradius of exit aperture 212. When multiple exit apertures 212 are servedby a single centrally positioned emitter electrode tip 320, distancesbetween the two may exceed ten times the radius of exit aperture 212.

The limited useful operational life of approximately several minutes ofcartridge 106 permits consistent charge injection of fluid 310 to bereliably achieved with micron diameter sized emitter electrodes. In someembodiments, emitter electrode 318 is a thoriated tungsten wireelectrode or lanthanum doped tungsten wire electrode having a diametergreater than 1 micron and less than 100 microns, however, other emitterelectrodes may be substituted. Use of such emitter electrodes providesmore than adequate charge injection at useful voltage levels anddrastically reduces the cost of manufacturing cartridge 106.

As discussed in further detail below with respect to orifice structure208, when energized, emitter electrode tip 320 electrostatically chargesfluid 310 as it passes through the path of emitter electrode tip 320 asit is exiting cartridge 106 through fluid output channel 314 prior tobeing dispensed through one or more exit apertures 212. That is, in oneembodiment of preferred operation, fluid 310, under pressure, exitsreservoir 302 through fluid output channel 314 past emitter electrodetip 320 and out through one or more exit apertures 212 in orificestructure 208. As fluid 310 passes over emitter electrode tip 320, itbecomes electrically charged and subsequently atomizes andself-disperses after exiting cartridge 106 through exit aperture(s) 212.

In a preferred embodiment, orifice structure 208 is moveable and slidesor rotates to position an exit aperture 212 into and out of alignmentwith fluid output channel 314 and emitter electrode 320. Orificestructure 208 can be moved between two basic states: 1) fluid outputchannel 314 closed to the environment and emitter electrode 318electrically insulated from environment (i.e., the non-dispensingposition); and 2) fluid output channel 314 open to the environment andorifice structure 208 is grounded (i.e., the dispensing position).Orifice structure 208 moves into the dispensing position to dispensefluid 310 from within reservoir 302 when a user squeezes lever 226 oranother similar activation mechanism. Grounding of orifice structure 208eliminates a shock hazard for the user when apparatus 100 is in itsdispensing position.

Turning now to FIGS. 4A-4C, linear orifice structure 208 includesinsulator 402 and conductor 404. Linear orifice structures are mostuseful for applications such as compact burners in which clogging issuesare less severe and a limited number of orifices are adequate to addressclogging issues during operation. The cost of the linear orificestructure is sufficiently inexpensive to allow cartridge 106 and itsassociated linear orifice structure to be disposable and to accommodateuse of a new cartridge 106 for each use of the apparatus.

Insulator 402 is an insulating support structure capable of supportingconductor 404. In one embodiment of the present invention, insulator 402is manufactured of PolyEtherEtherKetone (“PEEK”) however other materialsincluding, but not limited to, high temperature, high strengthengineering plastics may be substituted. Conductor 404 is electricallyconductive and is in contact with local ground. Conductor 404 includesexit apertures 212 or groupings of exit apertures 212 that align with acorresponding orifice 414.

In one embodiment of the present invention, circular or cylindrical exitapertures 212 have diameters ranging from approximately 30 microns toapproximately 125 microns. In another embodiment, circular orcylindrical exit apertures 212 have diameters ranging from approximately30 microns to approximately 500 microns. In yet another alternateembodiment, slits having widths ranging from approximately 30 microns toapproximately 125 microns may be substituted for circular or cylindricalexit apertures 212 of similar size. In still another alternateembodiment, slits having widths ranging from approximately 30 microns toapproximately 500 microns may be substituted for circular or cylindricalexit apertures 212 of similar size. This range is selected since, whenoperating at atmospheric background pressures, charged fluids exitingapertures 212 having a diameter or width less than approximately 125microns have surface electric field levels that are less than the spraylimiting electrical breakdown strength of normal atmospheric air. Incontrast, when the diameters of circular exit apertures (or the widthsof slit exit apertures) are greater than approximately 125 microns,spray development is abruptly disrupted when the surface electric fieldstrength (caused by increased applied emitter electrode voltage) exceedsthe breakdown field strength of the ambient air. However, when thediameters of circular exit apertures (or the widths of slit exitapertures) are maintained at a size less than approximately 125 microns,such breakdowns do not occur. In addition, the smaller the diameter orwidth of the aperture, the higher the electrical breakdown strength willbe, thereby allowing operation at higher altitudes.

Optimal operation of apparatus 100 may be achieved over a broad range ofconverter voltages provided that the spray fluid does not break down asdiscussed above. Optimal operation includes charged fluid dropletshaving a maximum output charge density, minimum droplet size, andminimum distribution span. The use of relatively smaller exit apertures212 also eliminates the need for control circuitry for maintainingoptimal converter voltage (i.e., voltage within a few percent of thebreakdown limit) as typically required by larger aperture devices.

Additionally, use of circular or cylindrical exit apertures 212 havediameters ranging from approximately 30 microns to approximately 125microns (or exit slits having widths within the same range) provides atleast three operational benefits. First, it allows the use ofinexpensive and unregulated power supplies 110 because spray behaviorwill not be detrimentally affected by power supply output fluctuations.Second, it allows a fixed operating voltage to be used since spraybehavior (i.e., flow rates and fluid properties) is not affected byvoltage converter operating voltage fluctuations. Insensitivity tovarying or inconsistent flow rates is particularly important forapplications involving unregulated blow-down or hand-pumped fluidsupplies as described herein. Third, the smaller the diameter of theexit aperture, the lower the minimum voltage converter operating voltagerequired to achieve optimal spraying. For instance, direct injectionatomizers having exit apertures with an approximately 50 micron diametercan be operated at operating voltages of less than approximately 1 kVwithout impact on flow rate.

Furthermore, since exit apertures having relatively small diameters asdiscussed above operate at maximum charge density, the fluid spraysexiting therefrom exhibit the narrowest possible size distribution. Thatis, these size distributions have droplet size spans at least threetimes narrower than those of conventional aerosol atomizers. The smallerthe diameter of the exit aperture, the narrower the droplet size span.

Most importantly, charged sprays exiting apertures having relativelysmall diameters as discussed above have well-defined size distributionscharacterized by the absence of large droplet “tails” and dropletssmaller than approximately 10 microns. Not only are such sprays free oflarge and wasteful droplet populations, but droplet inhalation is notpossible. The only inhalation hazard is associated with evaporated vaporas the droplets flow toward the target.

In the depicted embodiment, insulator 402 is a substantially rectangularbody manufactured of any suitable insulating material such as, but notlimited to, plastic, bakelite, nylon, ceramic, PEEK, glass, lexan, andthe like. In both dispensing and non-dispensing positions, insulator 402entirely covers cartridge receptacle 116 and isolates it from theexterior of the apparatus (with the exception of exit apertures 212),thereby constraining the high voltage provided by converter contact 228to emitter electrode 318 to the interior of apparatus 100 to prevent ashock hazard for the user.

As depicted in FIG. 4A, insulator 402 includes two orifices 414 arrangedin a linear manner. While the depicted embodiment includes twoindividual and selectable orifices, greater or lesser quantities oforifices may be substituted without departing from the scope of thepresent invention. Also, orifices and corresponding exit apertures neednot be identical and may be configured to meet specific needs.Additionally, non-linear embodiments may also be substituted. Oneexample of such an alternate embodiment is the six orifice, rotaryembodiment discussed below with respect to FIGS. 5 and 6A-6C.

A first longitudinal edge of insulator 402 includes a plurality ofsubstantially semi-cylindrical notches 418. Notches 418 are provided tofacilitate movement of orifice structure 208 as required to dispensefluid from reservoir 302. Notches 418 of insulator 402 mate withcorresponding indexing structures integral to the activating mechanism.These indexing structures index orifice structure 208 to the desiredposition (i.e., dispensing or non-dispensing) when lever 226 is actuatedby a user. That is, via engagement with notches 418, indexing structuresmove orifice structure 208 to a dispensing position in which an exitaperture 212 aligns with emitter electrode tip 320 to facilitateelectrostatic atomization, or to a non-dispensing position in whichinsulator 402 covers emitter electrode 318 and the external end of fluidoutput passage 314, thereby sealing cartridge 106 from, and electricallyisolating it from, the external environment.

In some embodiment of the invention, notches 418 also allow an operatorto select one of a plurality of orifices such as orifices 414. Suchselection may be desired when orifices having different characteristicsare included to allow a user to select a specific orifice configuration.However, even if all orifices are identical, an operator may wish toselect a new orifice if the current orifice is clogged or otherwiseunusable. To facilitate this feature, in the case of a linear orificestructure such as structure 208, lever 226 would be configured to permittranslation of orifice structure 208 without pressurization of cartridge106. One method of doing this is to disable the return stroke of lever226 when an operator is selecting an orifice and to enable the returnstroke of lever 226 when a user wishes to pressurize reservoir 302 in aneffort to spray fluid 310.

Orifices 414 in orifice structure 208, as illustrated, can havedifferent exit aperture sizes and configurations. An example, bothsingle and multiple openings are shown. Different configurations andsizes are selected based upon, for example, the fluid used, the sprayflow rate desired, and the intended use of the spray. Orifice structure208 includes varying exit aperture configurations to allow the user toselect the configuration most suited to the user's application. Forexample, use of an orifice having a large diameter exit aperture and/ormultiple exit apertures will provide a user with a higher flow rate. Or,in another example, user of an orifice having multiple skewed exitapertures may enhance lateral dispersion of the sprayed fluid. Anyconfiguration of exit apertures may be included without departing fromthe scope of the present invention.

As seen in FIGS. 4A-4C, orifice structure 208 includes two identicalorifices 414 a and 414 b. However, the exit apertures 212 located inconductor 404 that are located within orifices 414 a and 414 b whenorifice structure 208 is assembled vary. More specifically, the portionof conductor 404 located within orifice 414 a includes four (4) exitapertures 212 arranged as the corners of a square. Such a configurationmaximizes lateral dispersion of the sprayed fluid. In contrast, theportion of conductor 404 located within orifice 414 b includes a singleexit aperture 212 centrally located within orifice 414 b. This orificeprovides a single stream of fluid at a higher flow rate due to thelarger diameter of its exit aperture.

In addition, the incorporation of multiple orifices 414 within orificestructure 208 allows an operator to select a new orifice 414 if thecurrently used orifice 414 becomes clogged or otherwise unusable. Such afeature increases the likelihood that an operator will have the abilityto deplete all of fluid 310 in cartridge 106 prior to its replacement.

Interior face 330 of insulator 402 includes recess 408 and it isconfigured to mate with conductor 404 as best depicted in the explodedand assembled views of FIGS. 4A and FIG. 4B, respectively. That is,groove 408 includes linear groove portion 410 and a series of curvedgroove inlets 412. Each groove inlet 412 includes a correspondingorifice 414. As orifice extends through insulator 402 from its interiorsurface to an exterior surface, its diameter enlarges in asemi-spherical manner.

When orifice structure 208 is indexed to a dispensing position and exitaperture 212 and its surrounding conductor 404 are aligned with emitterelectrode 318, the electrically conductive conductor 404 and emitterelectrode 318 form a charge injection electrostatic atomizer whichelectrostatically charges fluid 310 in fluid output channel 314 to allowit to atomize and disperse upon exiting exit aperture 212. Conversely,when orifice structure 208 is indexed to a non-dispensing position,emitter electrode 318 is aligned with insulator 404 (rather thanconductor 404), which seals fluid output channel 314. In addition,emitter electrode 318 ceases to act as an electrostatic atomizer, thereis no current flow from emitter electrode 318, flow of fluid 310 isceased, and the high voltage present at the emitter electrode isisolated from the exterior of apparatus 100. This aspect of theinvention allows emitter electrode 318 to be continuously maintained atoperating voltage without damage to apparatus 100 or fluid 310 andwithout danger to an operator. This aspect also allows spraying of fluid310 to resume immediately upon indexing of orifice structure 208 to adispensing position via actuation of lever 226 without the need tocoordinate voltage or fluid profiles, as this position causes emitterelectrode 318 to realign with the conductor 404. This aspect of theinvention further minimizes both the turn-on and turn-off fluidtransients and orifice structure dribble. This is particularly usefulfor burst or pulsed-spray applications such as diesel injectors, whichtraditionally have a “sac” volume servicing the orifices. Contrary tothe situation with conventional “sac” designs, the exit aperture(s) ofthe present invention are not exposed to the external environment aftercut off and, therefore, fluid dribble cannot occur.

To spray fluid 310 from apparatus 100 (from reservoir 302 through fluidoutput channel 314 and through exit aperture 212), an operator activatesthe activating mechanism by squeezing lever 226 or the like with apressure similar to that used for grease or caulking guns. The squeezingof lever 226 causes the activating mechanism to index pressurizingmechanism 104 to fold the bottommost portion of cartridge 106 intoitself, thereby pressurizing cartridge 106 while simultaneously movingan exit aperture 212 of orifice structure 208 toward alignment withemitter electrode tip 320 (via engagement of indexing structures withnotches 418). The mechanical linkage of the activating mechanism isconfigured such that pressurization of cartridge 106 is complete justprior to aligning exit aperture 212 with emitter electrode tip 320.Since emitter electrode 318 is continuously energized to operatingvoltage by converter conductor 228 whenever cartridge 106 is seatedwithin cartridge receptacle 116, this mechanical arrangement causescharge injection atomization to occur as soon as the exit aperture 212is exposed sufficiently to fluid output channel 314 to permit fluidflow. The configuration of apparatus 100 is such that the exiting fluid310 is charged when it flows over emitter electrode tip 320 sufficientlyto atomize and self-disperse after leaving exit aperture 212 and anyfluid 310 that is not sufficiently charged cannot be expelled fromapparatus 100 (until it is fully charged). That is, fluid 310 atomizesand self-disperses after it exits apparatus 100. This feature ofapparatus 100 eliminates, or greatly minimizes, non-optimal atomizationsuch as that exhibited by conventional (non-electrostatic) atomizers,particularly during turn-on and turn-off. The charged spray exits exitaperture 212 and causes no shock hazard to the operator due to therelatively low current level (i.e., microampere current level) of thecharged spray.

When an operator ceases application of pressure to lever 226, orificestructure 208 returns to a sealed, non-dispensing position (i.e., one inwhich none of the exit apertures 212 is aligned with fluid outputchannel 314 and emitter electrode tip 320). Ceasing application ofpressure to lever 226 also causes pressurizing mechanism 104 to reducethe pressure exerted on cartridge 106 and the fluid 310 containedtherein. In one embodiment, pressurizing mechanism 104 is a piston andceasing application of pressure to lever 226 causes the piston toretract, thereby reducing the pressure exerted on cartridge 106 and thefluid 310 contained therein.

When cartridge 106 is completely exhausted and/or the operator wishes toremove cartridge 106 for some other purpose, pressure is removed fromlever 226 causing orifice structure 208 to return to its non-dispensingposition. Removal of cartridge 106 from cartridge receptacle 316 causeslower pin section 224 b to de-actuate water-proofed cartridge insertionstatus switch 222 mounted on pressurizing mechanism 104, therebybreaking the electrical connection between power supply 110 andelectrical circuitry 202. The breaking of this electrical connectionde-energizes voltage converter 204 and de-activates comparator circuitry206. This de-energization increases the life of the power supply andincreases safety for the operator by eliminating the shock hazard.

Rotary Orifice Structure

Referring now to FIGS. 5 and 6A-6C, depicted is apparatus 500 which issubstantially identical to apparatus 100 with the exception of orificestructure 508. That is, apparatus 500 includes orifice structure 508 inlieu of orifice structure 208 as discussed above with respect toapparatus 500. Rotary orifice structure 508 has the same features aslinear orifice structure 208 as best seen in the exploded, interiorassembled, and exterior assembled views of FIGS. 6A, 6B, and 6C,respectively. Rotary orifice structures having a limited number oforifices are ideal for applications involving the need for producingsprays with different flow rates or plume geometries.

More specifically, orifice structure 508 includes insulator 602 andconductor 604. Insulator 602 is an insulating support structure capableof supporting conductor 604. Conductor 604 is electrically conductiveand is in contact with local ground. Conductor 604 includes exitapertures 612 or groupings of exit apertures 612 that align with acorresponding orifice 614.

In one embodiment of the present invention, circular or cylindrical exitapertures 612 have diameters ranging from approximately 30 microns toapproximately 125 microns. In an alternate embodiment, slits havingwidths ranging from approximately 30 microns to approximately 125microns may be substituted for circular or cylindrical exit apertures612 of similar size. This diameter is selected for the variety orreasons discussed above with respect to FIGS. 4A-4C.

In the depicted embodiment, insulator 602 is a substantially circularbody manufactured of any suitable insulating material such as, but notlimited to, plastic, bakelite, nylon, ceramic, PEEK, glass, lexan, andthe like. In both dispensing and non-dispensing positions, insulator 602entirely covers cartridge receptacle 116 and isolates it from theexterior of the apparatus (with the exception of exit apertures 612),thereby constraining the high voltage provided by converter contact 228to emitter electrode 318 to the interior of apparatus 100 to prevent ashock hazard for the user.

As best depicted in FIG. 6A, insulator 604 includes six orifices 614arranged in a circular manner. While the depicted embodiment includessix individual and selectable orifices, greater or lesser quantities oforifices may be substituted without departing from the scope of thepresent invention. Also, orifices and corresponding exit apertures neednot be identical and may be configured to meet specific needs.Additionally, non-rotary embodiments may also be substituted.

The peripheral edge of insulator 602 includes a plurality ofsubstantially semi-cylindrical notches 618. Notches 618 are provided tofacilitate movement of orifice structure 508 as required to dispensefluid 310 from reservoir 302 as discussed above with regards toapparatus 100. Notches 618 of insulator 602 mate with correspondingindexing structures integral to the activating mechanism. These indexingstructures index orifice structure 508 to the desired position (i.e.,dispensing or non-dispensing) when lever 226 is actuated by a user. Thatis, via engagement with notches 618, indexing structures move orificestructure 508 to a dispensing position in which an exit aperture 212aligns with emitter electrode tip 320 to facilitate electrostaticatomization, or to a non-dispensing position in which insulator 602covers emitter electrode 318 and the external end of fluid outputpassage 314, thereby sealing cartridge 106 from, and electricallyisolating it from, the external environment.

In some embodiment of the invention, notches 618 also allow an operatorto select one of a plurality of orifices such as orifices 614. Suchselection may be desired when orifices having different characteristicsare included to allow a user to select a specific orifice configuration.However, even if all orifices are identical, an operator may wish toselect a new orifice if the current orifice is clogged or otherwiseunusable. To facilitate this feature, in the case of a rotary orificestructure such as structure 508, lever 226 would be configured to permitrotation of orifice structure 508 without pressurization of cartridge106. One method of doing this is to disable the return stroke of lever226 when an operator is selecting an orifice and to enable the returnstroke of lever 226 when a user wishes to pressurize reservoir 302 in aneffort to spray fluid 310.

Orifices 614 in orifice structure 508, as illustrated, can havedifferent exit aperture sizes and configurations, for example, eventhough only one exit aperture 612 is shown in each orifice 614.Different configurations and sizes are selected based upon, for example,the fluid used, the spray flow rate desired, and the intended use of thespray. In addition, the incorporation of multiple orifices 614 withinorifice structure 508 allows an operator to select a new orifice 614 ifthe currently used orifice 614 becomes clogged or otherwise unusable.Such a feature increases the likelihood that an operator will have theability to deplete all of fluid 310 in cartridge 106 prior to itsreplacement.

Interior face 606 of insulator 602 includes recess 608 configured tomate with conductor 604 as best depicted in the exploded and assembledviews of FIGS. 6A and FIG. 6B, respectively. That is, groove 608includes circular groove portion 610 and a series of linear grooveextensions 612. Each groove extension 612 includes a correspondingorifice 614. As orifice extends through insulator 602 from its interiorsurface to an exterior surface, its diameter enlarges in asemi-spherical manner as best seen in the exterior assembled view ofFIG. 6C.

Encased Rotary Orifice Structure

Referring now to FIGS. 7A and 7B, depicted are cutaway interior andexterior views, respectively, of encased rotary orifice structure 708.That is, apparatus 100 as described above with respect to FIGS. 1-3 mayincorporate encased rotary orifice structure 708 and fluid outputchannel 730 in lieu of orifice structure 208, emitter electrode 318, andfluid output passage 314 as discussed above with respect to apparatus100.

Encased rotary orifice structures 708 having a limited number ofconductor exit apertures 712 are ideal for applications involving theneed for producing sprays with different flow rates or plume geometries.Encased rotary orifice structures are also ideal for diesel or directinternal combustion engine applications in which multiple orifices areused to provide high instantaneous flow rates and rapid turn-on andturn-off transients.

Orifice structure 708 includes insulator 702, conductor 704, conductorexit apertures 712, dedicated emitter electrodes 718, case 720, solenoid722, armature 724, and insulating structure 734. Insulator 702 is aninsulating support structure capable of supporting conductor 704.Conductor 704 is electrically conductive and is in contact with localground via contact with grounded case 720. Conductor 704 includesconductor exit apertures 712 or groupings of conductor exit apertures712 that align with a corresponding orifice 714. Each conductor exitaperture 712 has a corresponding and dedicated emitter electrode 718.

Case 720 is a substantially cylindrical conductive case bounded on itsbottommost end by case floor 726. Case 720 encases and supports theelectrostatic atomizer components, namely, insulator 702, conductor 704,dedicated emitter electrodes 718, solenoid 722, armature 724, andinsulating structure 734. Insulating structure 734 is coupled to case720 and each emitter electrode 718 passes therethrough. Insulatingstructure 734 maintains each emitter electrode 718 in a fixed positionwith reference to its corresponding conductor exit aperture 712 and caseexit aperture 740 and ensures proper alignment of emitter electrodes 718therewith. Insulating structure 734 includes passages 736 to allow fluid310 to pass therethrough for atomization between emitter electrodes 718and conductor exit apertures 712/case exit apertures 740.

As best depicted in FIG. 7B, case floor includes eight case orifices 728arranged in a circular manner. While the depicted embodiment includeseight individual and selectable orifices, greater or lesser quantitiesof orifices may be substituted without departing from the scope of thepresent invention. Also, orifices and corresponding case exit aperturesneed not be identical and may be configured to meet specific needs.Further, multiple circular arrays of emitter electrode/conductor exitaperture/case exit aperture combinations may be incorporated to increasethe fluid flow rates. As orifice extends through case floor 726 from itsinterior surface to an exterior surface, its diameter enlarges in asemi-spherical manner as best seen in the exterior view of FIG. 7B.

Rotary orifice structure 708 includes multiple conductor exit apertures712 each serviced by a dedicated emitter electrode 718 to limit the feedpressure to levels well below the >1000 bar levels currently being usedin conventional diesel injectors. Regardless of the quantity ofconductor exit apertures, operation will be the same as describedherein. Emitter electrode supply voltage and feed pressure are fixed andapplied continuously. Spraying will occur whenever insulator 702 isrotated to a dispensing position as discussed herein, and sprayingceases whenever insulator 702 is rotated to a non-dispensing position.

In the depicted embodiment, insulator 702 is a substantially circularbody manufactured of any suitable insulating material such as, but notlimited to, plastic, bakelite, nylon, ceramic, PEEK, glass, lexan, andthe like. In both dispensing and non-dispensing positions, insulator 702entirely covers cartridge receptacle 116 and isolates it from theexterior of the apparatus (with the exception of conductor exitapertures 712 and case exit apertures 740), thereby constraining thehigh voltage provided to emitter electrodes 718 to the interior ofrotary orifice structure 708 to prevent a shock hazard for the user.

As best depicted in FIG. 7A, insulator 702 includes eight exit apertures712 arranged in a circular manner. While the depicted embodimentincludes eight individual and selectable exit apertures, greater orlesser quantities of apertures may be substituted without departing fromthe scope of the present invention. Also, orifices 740 and correspondingconductor exit apertures 712 need not be identical and may be configuredto meet specific needs.

In one embodiment of the present invention, circular or cylindricalconductor exit apertures 712 have diameters ranging from approximately30 microns to approximately 125 microns. In an alternate embodiment,slits having widths ranging from approximately 30 microns toapproximately 125 microns may be substituted for circular or cylindricalconductor exit apertures 712 of similar size. This diameter is selectedfor the variety or reasons discussed above with respect to FIGS. 4A-4C.

Orifices 714 in orifice structure 708 can have differently sized and/orconfigured conductor exit apertures 712, for example, even though onlyone conductor exit aperture 712 is shown in each orifice 714. Differentconfigurations and sizes are selected based upon, for example, the fluidused, the spray flow rate desired, and the intended use of the spray.

Exterior face 706 of insulator 702 includes recess 708 (not shown)configured to mate with one or more conductors 704. Exterior face 706 ofinsulator 702 is in intimate contact with the inwardly facing surface ofcase floor 726. Conductor(s) 704 are in positive electrical contact withcase 720 at all times.

Solenoid 722 is centrally positioned on the inwardly facing surface ofinsulator 702 and rotates armature 724, which is also affixed to theinwardly facing surface of insulator 702. Actuation of solenoid 722 cancause the orifice structure to be actuated in an oscillatory manner orwith continuous controllable rotation.

When solenoid 722 is to be controlled in an oscillatory manner, theperipheral edge of case 720 includes one or more indexing tabs (notshown) for the accurate positioning of insulator 702 in a dispensing ornon-dispensing position. The indexing tabs of case 720 mate withcorresponding indexing structures that are integral to the activatingmechanism. These indexing structures index insulator 702 to the desiredposition (i.e., dispensing or non-dispensing) when armature 724 isactuated by a user.

When insulator 702 is indexed to a dispensing position, conductor exitaperture 712 and its surrounding conductor 704 are axially aligned withits dedicated emitter electrode 718 and its corresponding case exitaperture 740 which causes the electrically conductive conductor 704 andemitter electrode 718 to form a charge injection electrostatic atomizerwhich electrostatically atomizes fluid 310 in fluid output channel 730.Conversely, when insulator 702 is indexed to a non-dispensing position,emitter electrode 718 is aligned with insulator 702 (rather thanconductor 704) which seals fluid output channel 730. In addition,emitter electrode 718 ceases to act as an electrostatic atomizer, thereis no current flow from emitter electrode 718, flow of fluid 310 isceased, and the high voltage present at the emitter electrodes 718 isisolated from the exterior of the dispensing apparatus. Only the fluidcontained in the low length to diameter ratio conductor exit apertures712 is potentially subjected to non-optimal atomization during orificestructure transition. This aspect of the invention allows emitterelectrodes 718 to be continuously maintained at operating voltagewithout damage to the dispensing apparatus or the fluid contained withinand without danger to an operator. This aspect also allows spraying offluid 310 to resume immediately upon indexing of insulator 702 to adispensing position without the need to coordinate voltage or fluidprofiles, as this position causes emitter electrodes 718 to realign withexit apertures 712.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

I claim:
 1. A portable apparatus for electrostatically dispensing fluidcomprising: an activating mechanism; a high voltage generator to providea high voltage; a power source to supply power to said high voltagegenerator; a disposable cartridge, said disposable cartridge including:a reservoir containing said fluid; a fluid output channel extending fromsaid reservoir through an exterior wall of a first end of saiddisposable cartridge; and a movable orifice structure located adjacentand external to said exterior wall of said first end of said disposablecartridge, said movable orifice structure including at least one exitaperture, a conductor, and an insulator, said at least one exit aperturepassing through said conductor, said conductor electrically groundedwhen said disposable cartridge is located in said dispensing position,said insulator positioned to cover an external end of said fluid outputchannel and said emitter electrode when said movable orifice structureis located in a non-dispensing position thereby isolating said emitterelectrode and said fluid from an environment external to said disposablecartridge, said movable orifice structure connected to said activatingmechanism to be positioned thereby relative to said channel when saiddisposable cartridge is located in said dispensing position; an emitterelectrode including an emitter electrode tip and an emitter electrodecontact, said emitter electrode contact located exterior to saiddisposable cartridge and said emitter electrode tip located internal tosaid disposable cartridge, said emitter electrode contact electricallyconnected to said high voltage generator for electrostatically chargingsaid fluid when said disposable cartridge is in a dispensing position,said emitter electrode tip positioned to substantially axially alignwith one of said at least one exit apertures when said movable orificestructure is in said dispensing position; and an emitter electrodechannel extending from said emitter electrode tip to said fluid outputchannel, said emitter electrode channel axially aligned with saidemitter electrode tip; a pressurizing mechanism connected to saidactivating mechanism to be driven thereby, said pressurizing mechanismlocated adjacent said disposable cartridge and in communication with asecond end of said disposable cartridge for deforming and pressurizingsaid disposable cartridge; a housing, said housing substantiallyenclosing at least a portion of said activating mechanism, said highvoltage generator, said power source, and said pressurizing mechanism,said housing including a first cartridge receptacle for detachablyreceiving said disposable cartridge; and a spray charge dissipationmechanism.
 2. An apparatus according to claim 1, wherein said spraycharge dissipation mechanism is at least one of the group consisting ofa static wick, a drag line, a brush strip, and combinations thereof. 3.An apparatus according to claim 1 wherein said high voltage generator isenergized when said disposable cartridge is secured in said cartridgereceptacle.
 4. An apparatus according to claim 1 wherein said movableorifice structure is linear or rotary.
 5. An apparatus according toclaim 1, wherein said insulator of said movable orifice structure isconnected to said activating mechanism via at least one notch.
 6. Anapparatus according to claim 1, wherein the movable orifice structure isrotary and further comprises: a solenoid coupled to said insulator; asecondary insulating structure surrounding said solenoid; a conductivecase coupled to said conductor, said conductive case including at leastone aperture, each of said apertures aligning with one of said at leastone orifice; and a plurality of secondary emitter electrodes coupled tosaid secondary insulating structure, each of said plurality of secondaryemitter electrodes aligned with one of said at least one orifice whensaid movable orifice structure is in said dispensing position.
 7. Anapparatus according to claim 6 wherein said solenoid is operated viacontinuous rotation or in an oscillatory manner.
 8. An apparatusaccording to claim 1, wherein said emitter electrode is a thoriatedtungsten wire electrode or lanthanum doped tungsten wire electrodehaving a diameter greater than 1 micron and less than 100 microns.
 9. Anapparatus according to claim 1 wherein said activating mechanismincludes a lever.
 10. An apparatus according to claim 1 wherein saidreservoir is formed of a flexible, electrically insulating material. 11.An apparatus according to claim 1 wherein a size of said at least oneexit aperture is less than 500 microns.
 12. An apparatus according toclaim 1 wherein a size of said at least one exit aperture is less than125 microns.
 13. An apparatus according to claim 1 wherein a size ofsaid at least one exit aperture is less than 90 microns.
 14. Anapparatus according to claim 1 wherein a size of said at least one exitaperture is less than 70 microns.
 15. An apparatus according to claim 1wherein said at least one exit aperture is a slit.
 16. An apparatusaccording to claim 15 wherein a width of said at least one exit apertureis less than 125 microns.
 17. An apparatus according to claim 15 whereina width of said at least one exit aperture is less than 70 microns. 18.An apparatus according to claim 15 wherein a width of said at least oneexit aperture is approximately 50 microns.